Rectus sheath hematoma (RSH) is generally not considered a reason for abdominal pain and its incidence as a cause of abdominal pain is unknown. RSH is a rarely seen but nonetheless an important disease causing abdominal pain. During contractions of the rectus abdominis muscle, the inferior epigastric artery must glide with the muscle to avoid tearing. When the inferior epigastric artery is torn, blood dissects along the rectus sheath leading to hematoma formation. We report a case of spontaneous rectus sheath hematoma due to Foley catheterization after acute urinary retention. In the current case, the rectus abdominis muscle stretched because of overdistended bladder. After the patient was catheterized to drain urinary retention, the rectus abdominis muscle contracted abruptly, and vessels were injured by rapid muscle contraction caused by Foley catheterization.